Devices of the subject character, sometimes referred to as "mules" in the art, conventionally take the form of a self-propelled truck having a bar affixed to and projecting longitudinally forwardly from the truck. A pair of laterally extending fixed jaws and a pair of laterally extending movable jaws are mounted on the bar. The movable jaws are coupled to hydraulics for pivoting the jaws between longitudinally extending parallel positions and laterally extending aligned positions opposed to and spaced from the fixed jaws. When it is desired to move a vehicle, the movable jaws are pivoted to their forward positions, the back jaws are positioned beneath coaxial vehicle tires, and the front jaws are pivoted to their lateral positions opposed to the fixed jaws in back of the tires. The entire jaw head and bar are then raised by mule hydraulics, so that the vehicle tires are captured between the jaws and raised off of the ground or floor. The vehicle can then be moved by the self-propelled truck.
A problem arises in situations where the mule jaws cannot be positioned beneath the vehicle tires for moving the vehicle, such as when pushing a vehicle onto a dynamometer or up an incline. In this situation, it has been conventional practice to mount a T-shaped head on the forward end of the mule bar for engaging the bumper of the vehicle, so that the mule can push the vehicle without the tires being captured between the jaws. However, the T-shaped head is quite heavy, and it is difficult for an operator to assemble the head to and remove the head from the mule. Furthermore, different vehicles have different bumper heights, requiring several T-shaped heads for a full product line. It is therefore a general object of the present invention to provide a device or mule for moving disabled vehicles of the described character in which the requirement for the removable heavy T-shaped heads of the prior art is eliminated. A more specific object of the present invention is to provide a disabled vehicle mover or mule of the described character in which the entire device is provided as an integral assembly requiring no assembly or disassembly by an operator for moving disabled vehicles to a repair station, a dynamometer, a test stand or the like.
In accordance with the present invention, the need for the T-shaped pusher heads of the prior art described immediately above is overcome and eliminated by providing free-spinning rollers along the outside front edges of each of the movable jaws. In situations where the device cannot be employed by capturing and lifting tires between the jaws, the mule is placed in an orientation in which the rollers engage the vehicle tires. The mule may then be used to push the vehicle by means of the rollers engaging the tires. The rollers are free to rotate as the tires turn, so that the mule can be employed for pushing the vehicle up an incline or onto a dynamometer.